Method for preparing recycled polymers

Patent metadata

Field	Value
Publication number	US-2025075050-A1
Application number	US-202318727594-A
Country	US
Kind code	A1
Filing date	Jul 24, 2023
Priority date	Sep 28, 2022
Publication date	Mar 6, 2025
Grant date	—

Abstract

A method for preparing a recycled polymer is provided. The method includes: bringing a recovered polymer containing an additive into contact with an impregnation solvent in an impregnation tank to obtain a slurry containing a swollen polymer and an eluate; separating the slurry into a solid mixture containing the swollen polymer and a liquid mixture containing the eluate in a solid-liquid separator; and obtaining a recycled polymer from the solid mixture and recovering the additive from the liquid mixture, wherein the impregnation solvent is a mixed solvent of two or more solvents.

First claim

1 . A method for preparing a recycled polymer, the method comprising:
bringing a recovered polymer containing an additive into contact with an impregnation solvent in an impregnation tank to obtain a slurry containing a swollen polymer and an eluate; separating the slurry into a solid mixture containing the swollen polymer and a liquid mixture containing the eluate in a solid-liquid separator; and obtaining a recycled polymer from the solid mixture and recovering the additive from the liquid mixture, wherein the impregnation solvent is a mixed solvent of two or more solvents.

2 . The method of claim 1 , wherein the additive is one or more selected from dioctyl phthalate, di(2-ethylhexyl)phthalate, dibutyl phthalate, benzyl butyl phthalate, diisononyl phthalate, and diisodecyl phthalate.

3 . The method of claim 1 , wherein the polymer is a polyvinyl chloride resin or a polyolefin resin.

4 . The method of claim 1 , wherein the impregnation solvent has a swelling index of 0.2 to 0.5 according to the following General Formula 1:

Swelling
⁢

index
⁢

(
SP
)

=

(

mass
⁢

of
⁢

the
⁢

impregnation
⁢

solvent
⁢

in
⁢

the
⁢

swollen
⁢

polymer

)

/

⁢

(

total
⁢

mass
⁢

of
⁢

the
⁢

swollen
⁢

polymer

)

[

General
⁢

Formula
⁢

1

]

5 . The method of claim 4 , wherein the impregnation solvent is a mixed solvent of a first impregnation solvent and a second impregnation solvent,
the swelling index of the first impregnation solvent is 0.01 to 0.2, and the swelling index of the second impregnation solvent is 0.5 to 0.99.

6 . The method of claim 1 , wherein the impregnation solvent is a mixed solvent of a first impregnation solvent and a second impregnation solvent,
the first impregnation solvent is one or more of isopropyl alcohol, toluene, cyclohexanol, benzene, cyclohexane, water, methanol, ethanol, propanol, butanol, and pentanol, and the second impregnation solvent is one or more of acetone, dimethyl sulfoxide, chloroform, ethyl acetate, nitrobenzene, dichloromethane, methyl ethyl ketone, dimethylformamide, tetrahydrofuran, dimethylacetamide, cyclopentanone, and cyclohexanone.

7 . The method of claim 6 , wherein a mass ratio of the first impregnation solvent to the second impregnation solvent is 1:0.1 to 1:10.

8 . The method of claim 7 , wherein the mass ratio of the first impregnation solvent to the second impregnation solvent is 1:0.5 to 1:3.

9 . The method of claim 1 , wherein the impregnation solvent is a mixed solvent of a first impregnation solvent and a second impregnation solvent,
the first impregnation solvent is isopropyl alcohol, and the second impregnation solvent is acetone or methyl ethyl ketone.

10 . The method of claim 1 , wherein the solid-liquid separator is a centrifugal decanter.

11 . The method of claim 1 , wherein the liquid mixture is supplied to a distillation column to separate the mixed solvent and the additive, and the separated mixed solvent is circulated to the impregnation tank.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Sang Ho
• Park Jong Suh
• Oh Hyun Taek
• Kim Do Dam
• Kang Jue Hyung
• Kim Jun Sik
• Ryu Jin Sook
• Cha Seon Cheol

Classifications

• C08J2323/28

  by reaction with halogens or halogen-containing compounds (C08J2323/32 takes precedence) · CPC title

• C08J2323/02

  not modified by chemical after treatment · CPC title

• B29B2017/001

  Pretreating the materials before recovery · CPC title

• B29K2023/00

  Use of polyalkenes {or derivatives thereof} as moulding material · CPC title

• B29K2027/06

  PVC, i.e. polyvinylchloride · CPC title